He didn't go home after his shift.
He couldn't.
The city felt too loud. Too unaware. Too human.
Instead, Tae-Hyun walked.
Past midnight stores. Past bridges pulsing with traffic. Past buildings where people slept believing monsters only lived in stories.
His body was restless.
Not tired.
Charged.
The woman in the chamber.
The word vessel.
The file D.H-01.
They weren't trying to cure humanity.
They were trying to replace it.
He reached the river without realizing it.
Cold air rolled off black water. Neon reflections fractured across its surface like broken data.
He leaned against the railing and closed his eyes.
Focused inward.
On the hum.
On the new logic moving through him.
On the aftertaste of that underground presence.
His heart slowed.
Blood pressure adjusted.
Muscle fibers coiled with unnatural potential.
He tested a thought.
Not command.
Intention.
The tremor in his right hand ceased.
The bruise on his knuckles warmed, then dulled.
Cells aligned.
Energy redistributed.
So he could do this.
On himself, at least.
Control was possible.
But in the lab…
with her…
it hadn't been.
Dr. Seo's hand on his wrist replayed with intrusive clarity.
The steadiness of her pulse.
The calm electricity of her touch.
The way the noise inside him had quieted.
It disturbed him more than power ever could.
He straightened.
This connection was not coincidence.
And coincidences did not survive in places like Helix.
He returned to the lab two nights later.
Same clothes. Same badge. Same invisibility.
But not the same mind.
This time, he watched.
Listened.
Mapped.
Learned the rhythm of the underground.
Shift rotations.
Access doors.
Names spoken when they believed no one was near.
Dr. Seo appeared at 11:47 p.m.
She always did.
Not rushed.
Not reluctant.
As if something down here called her the way the hum called him.
She crossed into a glass-walled analysis room and activated the central display.
Tae-Hyun positioned himself across the corridor, pretending to wipe a spotless surface.
From here, he could see her reflection.
And her work.
Biological modeling.
Neural harmonics.
Cellular responsiveness charts.
But threaded through all of it—
anomalies.
His anomalies.
The same irregular patterns he felt inside his own body.
She was studying something that should not exist.
And she knew it.
After several minutes, she stopped typing.
Her gaze lifted.
She looked straight at him.
This time, she did not look away.
"Han Jae-Min," she said.
His body stilled.
He turned.
"Yes?"
"How long have you been working in Section C?"
"Three days."
She stepped out of the room.
Walked toward him.
Her footsteps were soft.
Deliberate.
The closer she came, the quieter the hum grew.
Not weaker.
Clearer.
"I checked the sanitation logs," she said. "You were assigned to B7."
"I was redirected."
"By whom?"
"I don't know."
She stopped an arm's length away.
Close enough that he could see faint shadows under her eyes.
Close enough that her warmth altered the way his skin processed air.
Close enough that the system inside him shifted orientation.
Toward her.
"Your vitals are wrong," she said softly.
He raised an eyebrow. "You haven't examined me."
She met his gaze.
"I don't need to."
Silence stretched.
Then she did something unexpected.
She held out a small medical scanner.
"May I?"
He hesitated.
Every instinct told him no.
But something deeper said—
yes.
He extended his hand.
She scanned his wrist.
The device beeped once.
Then twice.
Then emitted a low, confused tone.
Her eyes flicked to the screen.
And then widened.
"…That's impossible," she murmured.
"What is?" he asked.
She slowly lifted her gaze.
"Your cellular feedback is adapting to my presence."
He felt it then.
The hum was not merely quiet.
It was… aligning.
As if her body created a frequency his no longer had.
As if she completed a missing circuit.
She withdrew the scanner.
But not her attention.
"Who are you really?" she asked.
A thousand answers waited.
He chose the only honest one.
"Someone who should be dead."
Her breath caught.
Not dramatically.
But enough.
The corridor camera turned.
A red light blinked.
She stepped back instantly.
Professional again.
Cold again.
"We shouldn't talk here," she said quietly. "If you're serious about what you just said… meet me outside after your shift."
Then she turned and walked away.
Leaving him alone with a body that no longer knew how to be neutral around her.
And a mind that understood something dangerous had just begun.
Not attraction.
Not yet.
Dependence.